After that, LeBron James launched "Uninterrupted" under the Bleacher Report umbrella.

Both sites have been hugely popular. Two years ago, "Uninterrupted" received a $16 million investment from Warner Bros. and Turner Sports. The Players Tribune said it had 2.6 million readers in December 2016, making it one of the top 40 online American sports properties.

More than 1,000 MLB players are signed up on "Infield Chatter," so fans have plenty of content to interact with already.

National League MVP Kris Bryant said, "[It] really helps us share and connect in ways that we haven't been able to anywhere else."